Page 32 - Mikuni Carburetor Catalog 21

TUNING/JETTING
The Jet Needle controls the fuel mixture in the mid- range (1/4-3/4) throttle position. The taper of the needle determines the amount of fuel. For example: the thinner the diameter of the needle, the more fuel will be drawn. The thicker the diameter of the needle, the less fuel can be drawn.
TWO TYPES OF NEEDLES
Single Taper Type
SERIES TYPE APPLICATION
#4
All 18mm Carburetors 22mm and 24mm Flange
#5
26mm-32mm Spigot 28mm-34mm Flange
#6 30mm-38mm Spigot
#7 40mm and 44mm Spigot
#8 HSR 42/45 Carbs
#9 RS and HS Carbs
6DH2
6F9
6CF1
6FJ6
6DH3
6L1
6DP17
6N1
6DP1
6DH4
6DH7
6DH8
6FL14
6F15
6DP10
6F13
6DJ30
D-1 through D-6 indicates diameter (mm) at each point.
A
62.3
62.3
61.5
62.3
62.3
62.3
62.3
62.3
62.3
62.3
62.2
62.2
62.1
62.2
62.4
64.2
64.7
B
28.0
28.9
29.5
35.2
22.0
37.0
32.1
37.0
28.9
25.5
28.5
20.3
26.7
19.8
26.5
32.8
26.3
D-1
2.511
2.516
2.512
2.505
2.512
2.512
2.518
2.514
2.511
2.520
2.516
2.538
2.538
2.535
2.51
2.50
2.51
D-2
2.511
2.516
2.512
2.505
2.512
2.512
2.518
2.514
2.511
2.520
2.516
2.538
2.538
2.538
2.51
2.46
2.51
D-3
2.466
2.475
2.429
2.505
2.458
2.512
2.518
2.514
2.476
2.440
2.505
2.436
2.538
2.461
2.44
2.46
2.45
D-4
2.295
2.210
2.240
2.376
2.286
2.335
2.372
2.278
2.312
2.258
2.316
2.208
2.233
2.208
2.26
2.24
2.09
D-5
2.000
1.949
1.974
2.040
1.948
1.826
1.834
1.672
1.748
1.915
2.009
1.827
1.649
1.979
1.56
1.97
1.66
D-6
1.660
1.678
1.710
1.606
1.607
1.313
1.141
1.058
1.075
1.575
1.688
1.497
1.218
1.649
.89
1.70
1.24
Taper Point
Taper Point (1)
Double Taper Type
Taper Point (2)
D-5
NEEDLE TAPER DIAMETER DIMENSION CHART
D-1 through D-5 indicates diameter (mm) at each point.
4E1
4J13
4L6
4J11
50.3
50.2
50.3
41.5
A
B
28.0
24.0
24.5
21.3
D-1
2.515
2.513
2.515
2.512
D-2
2.515
2.513
2.515
2.506
D-3
2.345
2.230
2.178
2.188
D-4
2.127
1.800
1.660
1.776
1.924
1.400
1.190
5F3
D-1 through D-6 indicates diameter (mm) at each point.
5EJ11
5FL11
5FL14
5FL7
5DP7
5J6
5L1
5J9
A
58.0
60.3
60.3
58.0
58.0
57.6
58.0
58.0
58.0
B
27.4
28.5
28.2
28.0
28.0
26.4
27.5
27.0
27.0
D-1
2.519
2.515
2.518
2.520
2.518
2.512
2.518
2.518
2.522
D-2
2.519
2.515
2.518
1.520
2.518
2.512
2.518
2.518
2.520
D-3
2.419
2.515
2.438
2.440
2.440
2.440
2.340
2.330
1.432
D-4
2.135
2.241
2.175
2.170
2.170
2.259
1.890
1.811
1.996
D-5
1.863
1.839
1.740
1.735
2.170
1.580
1.450
1.297
1.505
D-6
1.420
1.256
1.735
7DH5
7F7
7F6
7DH3
7DH2
D-1 through D-7 indicates diameter (mm) at each point.
A
72.2
72.3
72.3
72.5
75.3
B
27.4
33.1
29.0
28.1
31.6
D-1
2.98
2.99
3.00
2.98
2.99
D-2
2.98
2.99
3.00
2.98
2.99
D-3
2.94
2.99
2.95
2.96
2.99
D-4
2.78
2.80
2.68
2.80
2.84
D-5
2.44
2.54
2.41
2.47
2.66
D-6
2.08
2.28
2.14
2.11
2.27
D-7
1.72
2.02
1.87
1.76
1.92
A
10
20
B
30
40
D-1 through D-6 indicates diameter (mm) at each point.
6F5
6F4
6F8
6F16
A
62.3
62.3
62.3
64.6
B
38.1
32.0
34.0
31.2
C
19.0
19.4
21.5
18.4
D-1
2.515
2.515
2.512
2.520
D-2
2.456
2.442
2.512
2.404
D-3
2.454
2.436
2.386
2.400
D-4
2.364
2.206
2.214
2.201
D-5
2.098
1.939
1.945
1.941
D-6
1.840
1.678
1.688
1.679
50
60
70
32
D-1
D-2
D-3
D-4
D-5
D-6 D-7